Glass window and door panes, and including window and door structures substantially or wholly formed from glass, are ubiquitous and come in a range of different sizes, thicknesses, compositions and types. Most commonly, glass panes have been ‘float glass’ which is made by floating glass ingredients on a molten bed.
Float glass is typically 2-12 mm thick and was, until relatively recently, the choice for most windows and doors, particularly in homes. Many premises still have float glass panes and often a significant number. Unfortunately, this glass is dangerous when it is fractured or broken as it breaks into sharp shards or splinters. This is a dangerous situation and includes, for example, where a person breaks a float glass pane, damage is often done by the sharp broken edges that are created. Broken float glass panes require thorough removal to ensure all broken glass is removed, especially where children are likely to dwell such as in homes or public areas.
Toughened glass has in the past been a single pane whereas laminated glass is typically two or more panes attached together. Typically, toughened glass is between 3-12 mm and above thick. Laminated glass panes are somewhat larger, typically being between about 5.38-16 mm and above thick. Toughened glass panes are designed, when broken or fractured, to crumble into small pieces that have sharp edges. These small pieces typically pose a hazard to handling and of course have the obvious danger that small pieces may not be entirely removed. It should be noted that float glass will generally crack, break to large pieces as well as shards whereas toughened will crack and break to small pieces.
Toughened glass is intended to shatter and has a tendency to collapse when fractured or broken. Laminated panes often are not intended to shatter and only to retain fragments to the extent some strength remains from the remnants of the fractured glass pane. When laminated glass panes are broken or fractured, irregular sharp shards and fragments are created. Laminated glass is made up of two (or more) sheets of float glass joined together and if only one surface of the laminated glass has broken or fractured the laminated glass will remain as one, but if both surfaces have been broken or fractured, the glass pane will become unstable. It will be understood that in either the case of toughened or laminated glass panes, remaining parts of a fractured or broken glass pane are fragile to being handled.
It is also considered that broken toughened glass, for example, can release glass dust or fine particles of glass sufficient to possibly lead to respiratory difficulties. This is particularly relevant for glaziers, for example, who are regularly required to replace such broken glasses including balustrades and potentially have continual or prolonged exposure to such dust or particles.
Regardless of the type of glass pane or whether it is a glass object or contains glass such as a door, it is typical to simply remove a fractured or broken pane by literally knocking it out of its frame or support. This is obviously messy and relatively dangerous and far from ideal in many circumstances. For example, window or glass balustrades in multi-level buildings cannot simply be knocked out or allow any glass to fall outwardly away from the building in the process. However, toughened or laminated (both glass panes) glass panes that are broken or fractured, or parts of them, may fall on their own accord, even in a relatively gentle breeze or such as by the closing/opening of an internal door changing air pressure about the fractured window.
Any handling of the fractured or broken glass is most undesirable for the obvious reasons. Once the glass is removed, it is usually the case that fragments of the broken glass are found in the framing of windows or tracks of sliding doors or about the general location of the glass when fractured.
It is known to apply a tape or adhesive sheet to one or both sides of the remnants of a fractured or broken window pane, for example. However, this inherently can disturb the pane causing the fractured pane or any fragile remnants to fall. Notwithstanding, it is difficult to apply a tape or adhesive sheet in many circumstances due to the fragility of what remains, noting the difficulties in reaching the outside of the window or balustrade on multilevel buildings.
Of recent times, a method of removing broken or fractured window pane was developed. This is described in U.S. Pat. No. 7,231,747 (the 747' patent). In this patent, a two part foam is mixed at application by a spraying device and applied to remnants of a broken window. Once sprayed, the separated contents immediately mix and react creating the foam which expands and solidifies forming a unitary mass. The entire foam unitary mass enveloping the remnants of the broken glass pane are then removed.
This has shown to be a somewhat useful invention for its intended use of replacing the need to board external windows and glass doors and to a lesser degree those with fractured float glass. However, it is severely lacking for use with other glasses, particularly those that are especially fragile once fractured or broken or where the remnants are above ground level.
The method of the 747' patent requires that the entire window frame and surrounding areas be securely taped off before the foam is applied to the broken pane. As the foam is applied and expands, significant weight is added to the broken glass pane. The mere application of the foam to broken toughened glass can in itself cause the remnants to collapse. Further, applying a masking layer will often do likewise and create risks from falling glass fragments. Furthermore, the 747' patent also requires that once the foam has solidified, boards and later handles are required to remove the foam containing the broken glass. Obviously, this is most undesirable in multi-level buildings. This is emphasised by the 747' patent in that plywood or other pre-formed panels can be used to impart stability on a destabilised glass window pane. This can assist in holding the remnants in place until the foam solidifies, however, applying the plywood is not possible from the outside of a multi-level building on many occasions and its mere placement would cause destabilisation. Most undesirably, the expanded foam mass can easily damage most types of window frame such as powder coated aluminium or painted timber, and possibly surrounding material if not exactly taped off or if accidentally sprayed onto.
In addition to the 747' patent, other sprayable foaming protective compositions are known and are commercially available. Foaming glass protective methods however exhibit some tendency to cling to a surface when sprayed thereon and to dwell on the surface for a long period of time. Foams often contain at least 15 to 30 percent air, which is known to result in incomplete product to surface contact during dwell time, thus also reducing convenience.
Genesis of the Invention
The genesis of the present invention is a desire to provide a composition which can be sprayed on to broken window panes forming a film to stabilise them for their removal and which overcomes the disadvantages of the prior art, or to provide a useful alternative.